Pen



FIG. 1 is a front, right side perspective view of a pen embodying my new design;

FIG. 2 is a rear, right side perspective view thereof;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a rear elevational view thereof;

FIG. 5 is a right side elevational view thereof;

FIG. 6 is a left side elevational view thereof;

FIG. 7 is a top plan view thereof; and,

FIG. 8 is a bottom plan view thereof.

The broken lines showing features on the pen are included for the purpose of illustrating portions of the pen form no part of the claimed design. 

The ornamental design for a pen, as shown and described. 